In existing electronic systems it is well known to use printed circuit board assemblies intended to be mounted in shelves. The printed circuit boards assemblies or cards are disposed next to each other in the shelf and are oriented vertically to facilitate cooling. These printed circuit board assemblies typically include a printed circuit board on which are mounted electronic and optical components. At the rearmost edge the printed circuit board electrical and optical connectors are disposed for connection to a backplane or midplane provided in the shelf. The printed circuit board assemblies also typically use a faceplate mounted to the printed circuit board on the foremost edge. These faceplates serve a variety of purposes including providing mechanical stiffening, providing a protective front enclosure face for the printed circuit board assembly, providing a means for EMC/RFI shielding, providing a background for labelling purposes, and acting as a mounting point for display elements and switches. The faceplates may act also as a mounting point for connectors.
In electronic systems using a shelf/rack assembly where multiple equipment shelves are mounted in a stack arrangement in a rack, much intra-shelf signalling is accomplished over the backplane or midplane of the shelf. Signalling between cards within the shelf may be readily accomplished via signalling paths traversing the backplane.
This approach runs into difficulties when fiber optic signalling paths are required between circuit boards, and when inter-shelf signalling i.e. signalling paths between cards on different shelves are required. With optical connectors at the back of the shelf, cleaning and servicing of the optical fibers is difficult because of limited accessibility. Signalling paths between cards on different shelves encounters the difficulty of traversing the shelf-to-shelf separation as there is no backplane or midplane.
A known method of resolving this difficulty is to provide connectors on the faceplates of those cards requiring optical connections. Access for cleaning and servicing purposes is facilitated. Likewise, for those connections to be routed between shelves, connectors disposed on the faceplate allow cabling to be routed from the circuit card faceplate on one shelf to a circuit card faceplate on a different shelf.
Provision of faceplate connectors carries with it the problems of exposure to mechanical damage, and a problem of aesthetics. Cables terminating upon a faceplate connector are typically routed in a cable trough provided as part of the rack or shelf assembly. While traversing the cable trough the cables are relatively protected, however at some point the cables must exit the cable trough and range through space in front of the faceplate until terminating at the connector on the faceplate. The resulting placement tends to leave a portion of the cable exposed to accidental and incidental mechanical damage. Further, a plurality of cables terminating upon circuit card faceplates may begin to resemble a tangled skein, detracting from the aesthetics of the equipment installation and resulting in an unfinished or unprofessional impression of the equipment.
In view of the foregoing, it would be desirable to provide a faceplate for a circuit board which overcomes the above-described inadequacies and shortcomings by providing a mechanism which provides connector access but minimizes accidental and incidental contact to the cables and connectors.